Influence Of Adsorption Parameters Research Articles

CoAl-LDH decorated with cerium oxide as an efficient adsorbent for restoring low-concentration phosphate in wastewater.

The requirement for the removal of phosphorus (P) from wastewater has become progressively stringent, therefore, it is essential to remove low-concentration phosphate from secondary effluents through a tertiary treatment. One of the biggest challenges in removing phosphate from wastewater is the development of low-cost, green, and pollution-free adsorbents. In this study, novel, eco-friendly and low-cost CeO2 nanosphere modifying CoAl-LDH nanosheets (CoAl-LDH/CeO2) were successfully fabricated using a classical hydrothermal strategy. The microstructure and morphology of CoAl LDH/CeO2 were characterized using SEM, TEM, FTIR, XRD, TG, XPS, and BET techniques. The performance of the P adsorption from water for CoAl-LDH/CeO2 was investigated. The influences of adsorption parameters, such as adsorbent dosage, pH, phosphate concentration, adsorption time, and experimental temperature, were investigated through batch adsorption experiments. The batch adsorption experiments showed that the P removal by CoAl-LDH/CeO2 could reach 93.4% at room temperature within 60 minutes. CoAl-LDH/CeO2 showed ultrafast and high-efficiency adsorption for low concentration P contaminated wastewater. Pseudo-second order model exhibited better fitting with the kinetics of the phosphate adsorption, while the Freundlich model well-described the isotherm results (R2 > 0.999). Although Cl-, NO3-and SO42- coexisted in the solution, CoAl-LDH/CeO2 still possessed favourable selectivity for phosphates. More importantly, the adsorption capacities of CoAl-LDH/CeO2 retained over 85% after five cycles. Therefore, the low cost and sustainable utilization of CoAl-LDH/CeO2 for the phosphate removal from secondary effluent with phosphate at a low concentration highlights its potential application to alleviate eutrophication.

Deliberated system of ternary core–shell polythiophene/ZnO/MWCNTs and polythiophene/ZnO/ox-MWCNTs nanocomposites for brilliant green dye removal from aqueous solutions

In recent times, great attention has been given to developing extremely competent adsorbents for removing organic dyes from wastewater. Thus, to enhance their adsorption capability, a general strategy based on adsorbent surface modification with polymers has been proposed. This report demonstrates the potential of a ternary mixture of polythiophene/zinc oxide/multiwalled carbon nanotubes (PTh/ZnO/MWCNTs) and tertiary PTh/ZnO/oxidized multiwalled carbon nanotubes (ox-MWCNTs), which have been incorporated via an in-situ method of chemical polymerization through a simplistic two-way method. SEM and EDX outcomes show that ZnO and MWCNTs, or ox-MWCNTs, are well covered with PTh. Raman, FTIR, and XRD demonstrated the effective synthesis of PTh/ZnO/ox-MWCNTs and PTh/ZnO/MWCNTs nanocomposites with good interfacial interactions between the components. This report also examined the potential of these nanocomposites to remove brilliant green (B.G.) (a toxic dye) from a water solution. In addition, the influence of adsorption parameters, such as concentration, adsorption temperature, pH, and stirring time, was evaluated. B.G.’s adsorption percentage was affected by concentration, temperature, and time. B.G.’s maximum adsorption potential was 9.1 mg g −1 for PTh/ZnO/ox-MWCNTs and 8.3 mg g −1 for PTh/ZnO/MWCNTs, demonstrating the nanocomposites’ (NCs) potential for effective B.G. adsorption. The outcomes of the dye removal show that the dye removal process was spontaneous and endothermic, as evaluated by thermodynamic and kinetic criteria.

Selective adsorption and separation of toxic cationic dyes using hierarchically porous SDBS modified vaterite microspheres (Hr-SMV)

The application of hierarchically porous sodium dodecylbenzene sulfonate (SDBS) modified vaterite microspheres (Hr-SMV) for the selective adsorption of toxic cationic dyes has been explored in this work. Hr-SMV has been synthesized using a facile and low-cost precipitation method. X-Ray diffraction (XRD), Fourier transform infrared (FTIR), Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA) and N2 adsorption-desorption isotherms have been used to understand the crystal structure, surface area, morphology and surface functionalities of Hr-SMV. As prepared Hr-SMV possesses a surface area of 31.15 m2 g−1 and a hierarchical porous structure. Influence of adsorption parameters on the adsorption of two cationic dyes, Crystal violet (CV) and Methylene blue (MB) has been studied in detail using batch adsorption studies. Maximum adsorption capacities of 68.8 and 316.8 mg g−1 were exhibited by Hr-SMV for MB and CV, respectively. Further, Hr-SMV shows efficient adsorptive removal of other cationic dyes, including Basic fuchsine (BF) and Auramine O (AO). In binary mixtures of cationic dyes, Hr-SMV efficiently removes both cationic dyes, thus highlighting its prospect for practical applications. In binary mixtures of cationic and anionic dyes, Hr-SMV is found to selectively adsorb cationic dyes with high separation factors. Thus, Hr-SMV has been found to be a promising low-cost adsorbent for the efficient adsorption and separation of cationic dyes from effluents.

Synthesis and characterization of cellulose-based adsorbent for removal of anionic and cationic dyes

Synthetic dyes are widely used in textile, paper, plastic, and other industries, which are toxic and harmful to environment and human. Adsorption is an efficient method to control wastewater. Cellulose is an abundant, renewable, and eco-friendly polymer produced by plants and trees. An adsorbent for removal of dyes was successfully prepared by grafting amino-terminated hyperbranched polymer (NH2-HBP) and beta-cyclodextrin (β-CD) onto cotton fibers in this study. The adsorbent were characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy analysis. The influences of adsorption parameters in a batch mode including initial solution pH, contact time, and dye initial concentration were evaluated in the experiments. The experiment results showed that the adsorption equilibrium was reached within 6 h for Congo red and within 4 h for methylene blue. Both the adsorption isotherms and kinetic studies showed that the behaviors of Congo red and methylene blue removal by the adsorbent based on cotton fibers conformed with Freundlich model and fitted pseudo-second-order model, respectively.

Rare Earth Elements Removal from Water Using Natural Polymers

Adsorption of rare earth metals, Eu (III) and Nd (III) was investigated on a new environmental friendly material, thiourea functionalized cellulose. Before usage, the synthesized material was characterized by Fourrier Transform Infrared spectroscopy and energy dispersive X-ray analysis. The influence of adsorption parameters (adsorbent dosage, time, temperature and initial metal concentration) on adsorption capacity was investigated. Experimental data were fitted by using the pseudo-first-order and pseudo-second-order kinetic models. Simultaneously thermodynamic and equilibrium studies have been carried out using Langmuir, Freundlich and Sips isotherm. Maximum adsorption capacities were reached in 30 minutes at 298 K having the value of 27 mg/g for Eu (III) and 73 mg/g for Nd (III).

Adsorption behavior and mechanism of heavy metal ions by chicken feather protein-based semi-interpenetrating polymer networks super absorbent resin

Preparation and metal ions adsorption of CFP-g-PKA/PVA semi-IPN super absorbent resin.

Screening of agricultural waste for Ni(II) adsorption: Kinetics, equilibrium and thermodynamic studies

This study reports the adsorption of Ni(II) ions onto waste powders prepared from egg plant (EGP), sweet potato (SWP) and banana peels (BNP). The influence of adsorption parameters, such as pH, contact time, adsorbent weight, adsorbate concentration and temperature were investigated. Equilibrium was described by the Langmuir and Freundlich models. Ni(II) uptake was very fast reaching a maximum within 20 min of adsorbent contact with metal solution. Comparison of removal capacities for EGP, SWP and BNP indicated that EGP was more effective in removing Ni(II) from aqueous solution. The kinetic data fitted the pseudo second order model. Thermodynamic parameters ΔH and ΔS were negative which suggest that adsorption process was spontaneous. The results of Fourier transform infrared (FTIR) indicated several binding and chelating ions, such as carboxyl, carbonyl and hydroxyl groups on the biomaterials surfaces were responsible for Ni(II) adsorption.

Adsorption of Chitosan on PET Films Monitored by Quartz Crystal Microbalance

The adsorption behavior of chitosan on poly(ethylene terephthalate) (PET) model film surface was studied using the quartz crystal microbalance (QCM) technique. QCM with a dissipation unit (QCM-D) represents a very sensitive technique for adsorption studies at the solid/liquid interface in situ, with capability of detecting a submonolayer of adsorbate on the quartz crystal surface. Chitosan as well as PET were chosen for this study due to their promising biocompatible properties and numerous possibilities to be used in biomedical applications. As a first step, PET foils were activated by alkaline hydrolysis in order to increase their hydrophilicity. Model thin films were prepared from PET foils by the spin coating technique. The chemical composition of the obtained model PET films was analyzed using X-ray photoelectron spectroscopy (XPS) and their morphology was characterized by atomic force microscopy (AFM). Furthermore, the adsorption behavior of chitosan on these activated PET films and the influence of adsorption parameters (pH, ionic strength and chitosan solution concentration) were investigated in detail. Additionally, the surface chemistry and morphology of the PET films and the chitosan coated PET films were analyzed with XPS and AFM.

Voltammetric properties of electrodes modified by poly-[N-(9,10-anthraquinone-2-carbonyl)ethylenimine] and used in aqueous solution

Three differently loaded anthraquinone polymers have been prepared by condensation of 2-anthraquinonecarbonylchloride and poly(ethylenimine). They have been adsorbed on vitreous carbon or mercury electrodes by dipping the electrode in a solution of pyridine or methylene chloride containing 0.01–0.05% polymer. The influence of adsorption parameters and of electrochemical variables on the voltammetric behavior of the polymer-coated electrodes in aqueous buffer solutions is described. Changing the dip time in pyridine from 30 s to 5 min and changing the polymer concentration have very little effect on the apparent coverage (=1.3-1.8×10−9 mol cm−2) and peak shape. In contrast, an increase of the loading (the number of monomer units loaded with quinone) or the use of methylene chloride as a dip-coating solvent instead of pyridine affected the shape of the cathodic and anodic peaks which broaden and tend to separate. The peak shape is characterized by a tailing which tends to disappear at slow scan rate. The modifications of the peak shape and position when the scan rate is changed, have been shown to fit qualitatively with a proposed polylayer model in which electron (proton) transfer to the sublayer nearest the underlying conductor is slow. It has been observed that the weak acid dissociation constants for the dihydroanthraquinone and hydroanthraquinone anion are both different for the corresponding monomer in solution (pKA=8.65 and 11.6) and the adsorbed polymer (pKA=9 and 13).

Voltammetric properties of electrodes modified by poly-[ N-(9,10-anthraquinone-2-carbonyl)ethylenimine] and used in aqueous solution

Three differently loaded anthraquinone polymers have been prepared by condensation of 2-anthraquinonecarbonylchloride and poly(ethylenimine). They have been adsorbed on vitreous carbon or mercury electrodes by dipping the electrode in a solution of pyridine or methylene chloride containing 0.01–0.05% polymer. The influence of adsorption parameters and of electrochemical variables on the voltammetric behavior of the polymer-coated electrodes in aqueous buffer solutions is described. Changing the dip time in pyridine from 30 s to 5 min and changing the polymer concentration have very little effect on the apparent coverage (=1.3-1.8×10 −9 mol cm −2) and peak shape. In contrast, an increase of the loading (the number of monomer units loaded with quinone) or the use of methylene chloride as a dip-coating solvent instead of pyridine affected the shape of the cathodic and anodic peaks which broaden and tend to separate. The peak shape is characterized by a tailing which tends to disappear at slow scan rate. The modifications of the peak shape and position when the scan rate is changed, have been shown to fit qualitatively with a proposed polylayer model in which electron (proton) transfer to the sublayer nearest the underlying conductor is slow. It has been observed that the weak acid dissociation constants for the dihydroanthraquinone and hydroanthraquinone anion are both different for the corresponding monomer in solution (p K A =8.65 and 11.6) and the adsorbed polymer (p K A =9 and 13).